Cancers develop because of alterations, or mutations, in genes that normally promote controlled cell growth. Most cancers are caused by mutations that occur only in the tissue that is affected by the cancer....more

This rare type of thyroid cancer has several forms, depending on the mutations that cause it. Most cases of medullary thyroid cancer, though, are sporadic—they occur without any family history of thyroid cancer....more

Chromosome studies may be performed when a child is born with multiple birth defects. They may also be done when people have certain types of leukemias and lymphomas, to look for specific chromosome rearrangements associated with these types of cancers. Direct DNA studies look directly at the gene in question for an error....more

Testing methods vary from laboratory to laboratory and may affect the likelihood that the lab will identify a mutation in the gene if one is present. Different laboratory studies have the ability to detect different types of mutations. Accuracy will vary, depending upon the type of genetic testing method performed....more